African swine fever (ASF) is a highly contagious viral disease of swine with a mortality rate approaching 100 percent. African Swine Fever Virus (ASFV) is a double-stranded DNA virus with a complex molecular structure. Its large genome, encoding multiple virulence factors, allows for efficient replication, which takes place predominantly in the cytoplasm of monocytes and macrophages. Also, ASFV has the ability to interfere with cell signalling pathways, which leads to various modulations in the synthesis profiles of interferon and other cytokines. Sustained viremia favours the persistence of virions in blood and tissues of the convalescents, and the extended circulation of ASFV within the herd. ASFV has been spreading in the Caucasus since 2007, and in 2014 reached the eastern territory of the European Union. Outbreaks pose an economical threat to native pig rearing, especially since a single point source may easily develop into an epizootic event. There is currently no effective vaccine nor treatment for ASF, and eradication is possible only by prevention or the slaughter of diseased animals. This review paper summarizes the current state of knowledge about ASFV.